There are known kinds of drainage apparatus, in particular drainage channels or the like, in which the cover can be attached to the channel body by means of fixing elements.
Patent DE 195 04 869 Cl discloses a drainage channel with a cover grid that can be attached to a channel body. The grid is locked into position by means of a leaf-shaped locking spring, which comprises overhangs disposed opposite one another that engage recesses in the side walls of the channel body. After the overhangs have become engaged or locked into place, the locking spring of the grid rests in the interior of the channel body, in a substantially tension-free position. When the grid is set into the channel body and pressed down sufficiently to overcome the spring force, catch irons mounted on the cover grid, with arms bent at an angle, lock the grid into position.
This known drainage device, with a cover grid provided with a locking spring, presents the disadvantage that the locking spring is disposed in the interior of the channel body, in particular is transverse to its long axis. Hence the cross section of the channel is not completely free, which can cause blockages and/or makes cleaning substantially more difficult. Another disadvantage is that the walls of the channel body comprise recesses that serve to engage the locking springs and are disposed essentially at half height on the sides of the channel body. As this entails severe surface loading, the stability and the working life of the channel body are thereby impaired.